This invention pertains to bird feeders, such as the public uses in suspension from poles or branches, to attract and feed birdsxe2x80x94especially smaller, song birdsxe2x80x94and in particular to a bird feeder which is weight-discriminating to deny feeding access to larger, undesirable birds, and squirrels.
Bird feeders which discriminate by denying feed access to squirrels and larger birds and use spring-loaded perches are well known. However, in such prior art feeders, self-evidently, the springs employed increase in resistance, as the perch controlled thereby has a bird or squirrel alight: thereupon. If such bird or squirrel can learn to bear with some movement of the perch, without departing in anxiety, it can manage to acquire feed (albeit with some discomfort). More efficient weight-discriminating bird feeders are those which have a given weight in control of the perch. Typical of these is the Bird Feeder disclosed in U.S. Pat. No. 5,207,181, by Selmer M. Loken. Another is the Squirrel-Proof Bird Feeder, by Julio V. Cruz, set out in U.S. Pat. No. 5,309,867. Peter Morganson disclosed a Squirrel Proof Bird Feeder in his U.S. Pat. No. 5,676,089 of Oct. 14, 1997, and Duane Green, in U.S. Pat. No. 5,921,201, also disclosed a Squirrel-Proof Bird Feeder, issue date: Jul. 13, 1999. Each of these four, patented bird feeders is efficient and capable of denying feed to squirrels, and large, undesirable birds, and each uses a weight for the purpose. However, in each, there is a fixed weight, or a weight of given grams which, with the use of tools, can be selectively displaced to adjust for a weight-borne response. In addition, each has external limbs or arms which are susceptible of interference with branches, as they are set astride the feeder, or depend from a side thereof. Too, these limbs or arms, for being external, are subject to rust and/or corrosion, and fracture.
What has been needed is a more efficient, weight-discriminating bird feeder in which there is an unattached weight, that is a weight movable within the feeder, and wholly confined and obscured within the housing assembly, and having no externalized limbs or arms other than the perches themselves.
It is an object of this invention to meet the aforesaid need. In particular, it is an object of this invention to disclose a weight-discriminating bird feeder comprising a housing assembly; said assembly having a seed reservoir; seed ports formed in said assembly; perches (a) pivotably mounted to said assembly, and (b) extending outwardly from said assembly in adjacency to said ports; and unattached weights wholly confined within and obscured within said assembly; wherein said perches comprise means, responsive to a weight-loading thereof by birds alighting thereon, for displacing said weights.
It is also an object of this invention to set forth a weight-discriminating bird feeder comprising a housing assembly; said assembly having a seed reservoir; at least one seed port formed in said assembly; at least one perch (a) pivotably mounted to said assembly, and (b) extending outwardly from said assembly in adjacency to said one seed port; and an unattached weight wholly confined and obscured within said assembly; wherein said one perch comprises means responsive to a weight-loading thereof by a bird alighting thereon for displacing said weight.